Cyrtodactylus taybacensis, Pham & Le & Ngo & Ziegler & Nguyen, 2019

Pham, Anh Van, Le, Minh Duc, Ngo, Hanh Thi, Ziegler, Thomas & Nguyen, Truong Quang, 2019, A new species of Cyrtodactylus (Squamata: Gekkonidae) from northwestern Vietnam, Zootaxa 4544 (3), pp. 360-380 : 364-369

Cyrtodactylus taybacensis sp. nov.

( Figs. 3–5 )

Holotype. IEBR 4379 (Field No. SL 2016.400), adult male, collected by A.V. Pham and D.A. Giang on 14 October 2016 in the karst forest near Ca Nang Village (21˚54.440’N, 103˚31.390’E, elevation: 650 m asl.), Ca Nang Commune, Quynh Nhai District, Son La Province, northwestern Vietnam.

Paratypes. TBU 0 7, 0 8 (Field Nos. SL 2016.271, 272), adult males collected by A.V. Pham, T. Q.L. Hoang, L. M. Ha, N. B. Song, D. K.K.S. Vanh, and C. A. Lau on 25 September 2016 and IEBR 4380 (Field No. SL 2017.26), adult female, collected by N.B. Song and D. K.K.S. Vanh on 22 June 2017 in the karst forest near Pha Luong Village (21˚36.324’N, 103˚34.540’E, elevation: 720 m asl.), Phong Lai Commune, Thuan Chau District , Son La Province ; IEBR 4381 & 4382 (Field Nos. SL2016.403, 405), adult males and TBU 0 9 (Field No. SL 2016.404), adult female collected by A.V. Pham, L. M. Ha, O. V. Dieu and D. A. Giang on 15 October 2016 near Tua Thang Commune, Tua Chua District , Dien Bien Province (21˚56.933’N, 103˚27.803’E, elevation: 610 m asl.) .

Diagnosis. The new species can be distinguished from other members of the genus Cyrtodactylus by a combination of the following characters: medium size (SVL up to 97.5 mm); dorsal tubercles in 13–16 irregular rows; ventral scale rows 30–38; ventrolateral folds present without interspersed tubercles; each thigh with 11–13 enlarged femoral scales; femoral pores absent in males and females; precloacal pores 11–13 in males, five or 15 pitted scales in females, in a continuous row; postcloacal tubercles two or three; lamellae under toe IV 16–20; subcaudal scales transversely enlarged; dorsal head with dark brown marking, oval, triangle and arched shape; five brown dorsal bands between limb insertions.

Description of holotype. Adult male, snout-vent length (SVL) 85.7 mm; body elongate (AG/SVL 0.46); head distinct from neck, elongate, depressed (HL/SVL 0.28, HW/HL 0.67, HH/HL 0.41); supranasals in contact with each other anteriorly, separated from each other by a small scale posteriorly; nares oval, surrounded by supranasal, rostral, first supralabial, and three postnasals; loreal region concave; snout long (SE/HL 0.38), round anteriorly, longer than diameter of orbit (OD/SE 0.68); snout scales small, round, granular, larger than those in frontal and parietal regions; eye large (OD/HL 0.26), pupils vertical; upper eyelid fringe with spinous scales; ear opening oval, obliquely directed, small in size (ED/HL 0.07); rostral wider than high (RH/RW 0.74), bordered by first supralabial, nostril and supranasal on each side; mental triangular, as wide as rostral (RW 3.6 mm, MW 3.5 mm), wider than high (ML/MW 0.74); postmentals two, enlarged, in contact with mental anteriorly, first infralabial laterally, and eight small scales posteriorly; supralabials 10/11; infralabials 9/9.

Dorsal scales granular; dorsal tubercles round, three or four times larger than the size of adjoining scales, conical, present on occiput, back and tail base, each surrounded by 9 or 10 granular scales, in 15 or 16 irregular longitudinal rows at midbody; ventral scales smooth, medial scales two times larger than dorsal scales, round, subimbricate, in 34–36 longitudinal rows at midbody; lateral skin folds distinct, without tubercles; gular region with homogeneous smooth scales; ventral scales between mental and cloacal slit 177; precloacal groove absent; three rows of enlarged scales present in posterior region of pore-bearing scales; enlarged femoral scales present; femoral pores absent; precloacal pores 13, in a continuous row.

Fore and hind limbs moderately slender (ForeaL/SVL 0.18, CrusL/SVL 0.23); dorsal surface of forelimbs covered by small scales, slightly larger than underside scales, without tubercles; dorsal surface of hind limbs covered by distinctly developed tubercles; interdigital webbing weakly developed; subdigital lamellae: finger I 14/ 14 (with 6/6 basally broadened lamellae), finger II 16/15 (7/6), finger III 17/18 (6/6), finger IV 18/18 (7/7), finger V 16/17 (6/5), toe I 15/15 (6/6), toe II 15/16 (6/6), toe III 17/17 (6/6), toe IV 20/19 (9/8), toe V 19/20 (7/7).

Tail regenerated; postcloacal tubercles 2/2; dorsal tail base with distinct tubercles; subcaudals distinctly enlarged in the original part, smooth.

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Coloration in life. Ground color of dorsal head and back yellowish brown; snout region yellow with two dark spots; dorsal head with dark marking, oval, triangle and arched shape; a dark stripe extending from posterior corner of eye to above tympanum; labials yellow; neck with some large dark blotches, forming a discontinuous band anteriorly and a continuous band posteriorly; dorsum with five transverse dark brown bands between fore and hind limb insertions, edged in yellow anteriorly and posteriorly; dorsal surface of fore and hind limbs with dark brown blotches; dorsal surface of tail yelowish brown with two dark bands at base, regenerated part greyish cream; chin, throat, chest, belly and lower limbs pinkish white; ventral surface of tail greyish ( Fig. 3 ).

Sexual dimorphism and variation. The females differ from male specimens in the absence of hemipenial swellings at the tail base and having a larger size. The males have 11–13 precloacal pores (versus 5 or 15 pitted scales in females). The tails of paratypes (TBU 0 7 and IEBR 4380) are complete, greyish cream with nine dark brown bands, subcaudals distinctly enlarged approximately three fourths of tail length. For other morphological characters see Table 1.

Distribution. Cyrtodactylus taybacensis sp. nov. is currently known from Tua Chua District in Dien Bien Province and Thuan Chau and Quynh Nhai districts in Son La Province, Vietnam ( Fig. 1 ).

Etymology. Specific epithet “ taybacensis ” is a toponym in reference to the type locality of the species, meaning “from northwestern region”. For the common names we suggest Taybac Bent-toed Gecko (English) and Thạch sùng ngón tây bǻc (Vietnamese).

Natural history. Specimens were found at night between 19:00 and 21:00, on trees near limestone cliffs and in rock crevices, approximately 0.5–1.5 m above the ground, at elevations between 600 and 720 m asl. The surrounding habitat was disturbed evergreen karst forest of medium hardwood and shrub. The relative humidity was approximately 75–85% and the air temperature ranged from 25 to 34 o C.

Comparisons. We compared the new species with its congeners from Vietnam and neighboring countries in mainland Indochina, including Laos, Cambodia, Myanmar, China (Yunnan), Thailand, and peninsular Malaysia based on examination of specimens (see Appendix) and data obtained from the literature ( Smith 1917, 1921a, b, 1935; Taylor 1963; Ulber & Grossmann 1991; Ulber 1993; Bauer 2002, 2003; Bauer et al. 2002, 2003, 2009, 2010; Ziegler et al. 2002, 2010, 2013; Pauwels & Sumontha 2014; Pauwels et al. 2004, 2013, 2014a, b, 2016; Nguyen et al. 2006, 2014; Hoang et al. 2007; Orlov et al. 2007; Grismer & Ahmad 2008; Ngo 2008, 2011; Ngo & Bauer 2008; Ngo & Chan 2010, 2011; Ngo & Grismer 2010, 2012; Ngo & Pauwels 2010; Ngo et al. 2008, 2010; Sumontha et al. 2010, 2012, 2014; Chan-ard & Makchai 2011; David et al. 2011; Schneider et al. 2011; Luu et al. 2011, 2014, 2015, 2016a, b, c; Grismer et al. 2012, 2016, 2017; Kunya et al. 2014, 2015; Nazarov et al. 2014; Panitvong et al. 2014; Le et al. 2016; Connette et al. 2017; Pham et al. 2017; and Nguyen et al. 2015a, 2017). The new species can be distinguished from other known species of Cyrtodactylus by morphological characters (see Table 2). Below we compared the new species from the closely related species from northern Vietnam and northern Laos.

In general appearance, Cyrtodactylus taybacensis sp. nov. is similar to C. bichnganae Ngo & Grismer , C. cf. bichnganae , C. bobrovi Nguyen, Le, Pham, Ngo, Hoang, Pham & Ziegler , C. chauquangensis Hoang, Orlov, Ananjeva, Johns, Hoang & Dau , C. cucphuongensis Ngo & Chan , C. huongsonensis Luu, Nguyen, Do & Ziegler , C. martini Ngo , C. puhuensis Nguyen, Yang, Le, Nguyen, Orlov, Hoang, Nguyen, Jin, Rao, Hoang, Che, Murphy & Zhang , C. otai Nguyen, Le, Pham, Ngo, Hoang, Pham & Ziegler , C. spelaeus Nazarov, Poyarkov, Orlov, Nguyen, Milto, Martynov, Konstantinov & Chulisov , C. soni Le, Nguyen, Le & Ziegler , C. sonlaensis Nguyen, Pham, Ziegler, Ngo & Le , C. vilaphongi Schneider, Nguyen, Duc Le, Nophaseud, Bonkowski & Ziegler , C. wayakonei Nguyen, Kingsada, Rösler, Auer & Ziegler. Cyrtodactylus taybacensis sp. nov. differs from C. bichnganae by having more precloacal pores in males (11–13 vs. 10) and the absence of femoral pores on each thigh in males (vs. 9); from C. bobrovi by having fewer ventral scale rows (30–38 vs. 40–45), the presence of enlarged femoral scales (vs. absent), the presence of enlarged subcaudals (vs. absent), more preloacal pores in males (11–13 vs. 5), and fewer lamellae under toe IV (16–20 vs. 21–22); from C. chauquangensis by the presence of enlarged femoral scales (vs. absent) and having more precloacal pores in males (11–13 vs. 6); from C. cucphuongensis by the presence of precloacal pores in males (vs. absent), having fewer ventral scale rows (30–38 vs. 42), fewer lamellae under finger IV (17–19 vs. 21) and under toe IV (16–20 vs. 24); from C. huongsonensis by having more enlarged femoral scales on each thigh (11–14 vs. 7–9), more precloacal pores in males (11–13 vs. 6), and fewer ventral scale rows (30–38 vs. 41–48); from C. martini by having more precloacal pores in males (11–13 vs. 4), fewer ventral scale rows (30–38 vs. 39–43), and fewer lamellae under toe IV (16–20 vs. 22–24); from C. puhuensis by having more precloacal pores in males (11–13 vs. 5) and fewer lamellae under toe IV (16–20 vs. 23); from C. otai by having more preloacal pores in males (11–13 vs. 7–8), the presence of enlarged femoral scales (vs. absent), and the presence of enlarged subcaudals (vs. absent); from C. soni by having more enlarged femoral scales on each thigh (11–14 vs. 8–9), more precloacal pores in males (11–13 vs. 6–8), the absence of femoral pores in males (vs. 6–8 on each thigh), and fewer ventral scale rows (30–38 vs. 41–45); from C. sonlaensis by its larger size (SVL reaching 97.5 mm vs. 83.2 mm), the absence of femoral pores in males (vs. 13–15 on each thigh), more precloacal pores in males (11–13 vs. 8), and fewer enlarged femoral scales on each thigh (11–14 vs. 15–17); from C. spelaeus by having more precloacal pores in males (11–13 vs. 8–9) and fewer lamellae under toe IV (16–20 vs. 22–24); from C. vilaphongi by the presence of enlarged subcaudals (vs. absent), the presence of of enlarged femoral scales (vs. absent), and the presence of pitted scales in females (vs. absent); and from C. wayakonei by having fewer dorsal tubercle rows (13–16 vs. 16–19), the presence of enlarged femoral scales (vs. absent), and more precloacal pores in males (11–13 vs. 6–8).

Morphologically, Cyrtodactylus taybacensis sp. nov. resembles C. cf. bichnganae . However, the new species can be distinguished from the latter by having more precloacal pores in males (11–13 vs. 7–9 in C. cf. bichnganae ) and the absence of femoral pores on each thigh in males (vs. 3–10 in C. cf. bichnganae ).

Figures

FIGURE 1. Map of sampling sites of Cyrtodactylus taybacensis sp. nov. in northwestern Vietnam: 1) Thuan Chau District; 2) type locality in Quynh Nhai District, Son La Province; and 3) Tua Chua District, Dien Bien Province.

FIGURE 3. The male holotype of Cyrtodactylus taybacensis sp. nov. in life (IEBR 4379).

FIGURE 4. Cloacal region of the holotype of Cyrtodactylus taybacensis sp. nov. (IEBR 4379).

FIGURE 5. The female paratype of Cyrtodactylus taybacensis sp. nov. in life (TBU 09).